If you’ve downloaded a song in the past few years, it’s in large part because of Justin Frankel. Seven years ago, when he was just eighteen, he invented Winamp, the first software program that made it easy to play digital music on your computer. A few years later, he created Gnutella: the vast, and vastly controversial, online network that lets you swap songs. The fact that Frankel secretly did the latter while working at America Online, the company behind his multimillion-dollar buyout, made him both the Internet’s greatest punk — and hero. Now he’s about to punk the industry again.